Strange readings on EGT 1 and 2

Did you notice anything unusual in the EGT indications on the G3X? When you had the solid Lane A light, did you bring up the FADEC Info on the G3X? That should have given you a general diagnosis.

Mike wrote:

Did you notice anything unusual in the EGT indications on the G3X? When you had the solid Lane A light, did you bring up the FADEC Info on the G3X? That should have given you a general diagnosis.

Hi Mike - I didn't capture the exact errors on the G3X FADEC screen before I shut down.  Lots of piloting going on as I had lost engine power and was focused on getting down.  I do recall it there was a EGT error though.

I'm trying to attach a couple of graphs that show the decay of the data on EGT 2 and 1 - can't seem to make it happen.  Will post a link if I can ...

BUDS data would certainly not hurt to look at. 

Charles,

The Buds data would help, but even though these are fancy electronic engines it still often comes down to fuel and spark.

Looking at your EGT graphs, I think this indicates misfires on those two cylinders. This is also supported by what you experienced with the rough running. The chances of injectors failing on both cylinders are slim and there are no injector components shared by both cylinders. So that leads us to "spark". The logical thing to do is look at components that are shared by cylinders 1 & 2, and that points us to either Coil 1 or Coil 2. Coil 1 provides spark to cylinders 1 & 2 bottom plugs, and coil 2 provides spark to the top plugs of those same cylinders. 

I would start by testing coils 1 & 2 with an ohm meter as per the MMH. Also, check the primary side connectors for a secure fit. I don't remember when the new style primary side connectors went into production, but the earlier Faston style connectors had issues with vibrating themselves loose and would cause misfires.

Jeff Blakeslee wrote:

Charles,

The Buds data would help, but even though these are fancy electronic engines it still often comes down to fuel and spark.

Looking at your EGT graphs, I think this indicates misfires on those two cylinders. This is also supported by what you experienced with the rough running. The chances of injectors failing on both cylinders are slim and there are no injector components shared by both cylinders. So that leads us to "spark". The logical thing to do is look at components that are shared by cylinders 1 & 2, and that points us to either Coil 1 or Coil 2. Coil 1 provides spark to cylinders 1 & 2 bottom plugs, and coil 2 provides spark to the top plugs of those same cylinders. 

I would start by testing coils 1 & 2 with an ohm meter as per the MMH. Also, check the primary side connectors for a secure fit. I don't remember when the new style primary side connectors went into production, but the earlier Faston style connectors had issues with vibrating themselves loose and would cause misfires.

Thanks Mike.  I've attached the BUDS data if anyone can see something in there that's helpful - the issue occurred in the last 90 minutes of data.  I have checked the Faston connectors for secure fit.  I did have to replace the coil that serves Cyl 3 recently, but that was reproducible - Lane B always ran rough.  This situation hasn't re-occurred and was on both cyl 1 and 2 according to the BUDS data.  Given the error showed up on Lane A, does that implicate a specific coil?